1. Field of the Invention
The present invention relates to an apparatus controlling method and a transmission device suitably used for performing control between apparatuses interconnected via an IEEE1394 serial communication bus for example.
2. Description of the Related Art
An AV apparatus capable of mutually transmitting information via a network provided by an IEEE1394 serial communication bus has been developed. According to this network, by transmitting a predetermined command (selected from AV/C Command Transaction Set, hereinafter referred to as the AV/C commands), it is possible to control the AV apparatus connected to the network. Details of the AV/C command are written in AV/C digital Interface Command Set General Specification which is made public by 1394 Trade Association.
Now, in a configuration in which a plurality of AV apparatuses are interconnected, for example, if one television receiver and a plurality of video apparatuses (video decks) are interconnected, the television receiver, serving as an input apparatus to which video signal is inputted, has to select a video apparatus serving as a signal source. Here, according a prior art system for example, in which the interconnection is made by means of conventional video cable for transmission of an analog video signal, there is already a variety of apparatuses provided with a capability of an action (so-called the auto-play capability) in which signal receiving action in the input apparatus is automatically carried out by a control from the signal source apparatus. In addition, it is convenient for a user, if there can be an auto-recording action in which a video signal being received by the television receiver can be selected and recorded by the video apparatus.
According to the proposed AV/C commands, however, the above control of selecting the input apparatus and outputting apparatus is basically performed by a center controller located on the bus line. Therefore, the center controller has to have a heavy burden. Another problem is that without the command from the center controller, no selection of the input apparatus or the output apparatus can be made individually on any of the apparatuses on the bus line.
In order to solve the above described problems, the applicant of the present invention proposed a procedure (disclosed in the Japanese Patent Application No. 11-283452) in which a presetting such as settings that determines an input state can be made in other apparatuses located on the bus line by using the AV/C commands and so on.
Now, according to the IEEE1394 serial communication bus, if there is a change in a configuration of the apparatuses connected to the bus, i.e. when a new apparatus is connected to the bus, or an apparatus which has been connected to the bus is removed from the bus, a bus resetting is performed. In this bus resetting process, the controller on the bus controls each of the apparatuses connected to the bus to be given a new identification data. (This identification data is called the node ID.) again.
If the presetting above described has been made, and then the bus resetting is performed to change the node ID, the preset apparatus, which recognizes the opponent apparatus by the old node ID, can no longer identify the opponent apparatus. Thus, there is a problem that the preset state cannot be maintained.
Further, according to the auto-play action described above, the commanding apparatus is basically only one of the outputting apparatus and the inputting apparatus, and the selection of the commanding apparatus is made in advance. Therefore, it is difficult to perform an equal action by the commands from the opponent apparatus to the selected apparatus.
It is therefore a primary object of the present invention to make possible that a cooperative action such as the auto-play action is maintained between the apparatuses interconnected via a bus such as the IEEE1394 bus, even after the execution of the bus resetting operation and the like.
A second object of the present invention is to make possible that in a cooperative action such as the auto-play operation arranged between the apparatuses interconnected via a bus such as the IEEE1394 bus, commands for the action can be issued from the apparatus on whichever side.
A first aspect of the present invention provides an apparatus controlling method for data transmission between a first apparatus and a second apparatus connected to a predetermined bus line, wherein presetting of settings for inputting or outputting of data in the first apparatus is directed by a transmission of a command in a predetermined format via the bus line, wherein an identification data unique to the second apparatus being transmitted upon the transmission of the directing command, and wherein the first apparatus storing the transmitted unique identification data when performing the presetting in accordance with the command.
With the above arrangement, it becomes possible for the first apparatus in which the presetting is made to identify the second apparatus on the bus line at any time based on the unique identification data stored.
A second aspect of the present invention provides an apparatus controlling method for performing control between apparatuses connected to a predetermined bus line, wherein settings of output status in a first apparatus can be preset by a transmission of a predetermined command from a second apparatus so that data outputted from the first apparatus is received by the second apparatus, and wherein the issuance of the command from the second apparatus being made by a direction from the first apparatus.
With the above arrangement, it becomes possible to perform the presetting in the first apparatus for data transmission between the first apparatus and the second apparatus by the direction from the first apparatus.